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Monitor glitches when using a VGA cable

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2 replies to this topic

#1 ronalbruno


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Posted 02 May 2018 - 06:44 PM

Hello, so to start off.. my build:

2 x HP V244h 23.8 inch Monitors

1 x HP Elitebook 840 G4 Laptop - Interl Core i5-7300U CPU @ 2.60 GHz processor - 16 GB of RAM

1 x HP Ultraslim Docking Station

1 x NEC Display 48" Commercial-Grade Large Format Display

My issue is that I'm using a Display Port to HDMI adapter to connect one monitor and the TV (Display) to the docking station (HDMI goes into monitors, using seperate HDMI cords of course). The other monitor is connected to the docking station using a VGA cable. Now, the monitor that is connected using the VGA cable will glitch every so often, where the screen will flicker and goes to black for a couple seconds, or it "sees double" where images shift while this is happening. You may suggest that I use a different type of cable, but the docking station only has room for a VGA connection (2 Display Port and 1 VGA port in total).

I've tried the following:

  • Switch monitors (issue persists on whichever monitor is connected using the VGA cord)

  • Switched VGA cord (issue persists, no matter which VGA cord I use

  • Updated video card drivers.

I've run out of resources at this moment, any help is much appreciated.

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#2 mjd420nova


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Posted 03 May 2018 - 06:16 PM

I'm not a big fan of adapters as they often introduce these kinds of things.  The HDMI has a lot of handshaking going on between the display device and the video port, throw in an adapter and these signals get confused or lost and this forces a reset signal on the port to re-establish proper handshaking protocols.  

Edited by mjd420nova, 04 May 2018 - 04:41 PM.

#3 mightywiz


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Posted 04 May 2018 - 09:09 AM

display port to dvi or hdmi are a straight through cable, but when you use a display port to vga then a decoder/encoder chip is involved and that's probably what your seeing.   it also could be that you have a bad display port to vga adapter.  I use DP to HDMI all the time and never have had an issue.


now when i use a my hdmi to vga adapter i have issues when the video resolution makes a change per the program i'm using.  the screen will go black and it will take a few seconds for it to sync to the new resolution.

Edited by mightywiz, 04 May 2018 - 09:09 AM.

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